Question

Solve (29 - 7.2) - 0.8.

Answer 1

We know that $(x-y)-z=x-(y+z)$, for all numbers $x$, $y$ and $z$.

Since the above is true for all the numbers, it must be true for $x=29$, $y=7.2$ and $z=0.8$ also.

So, $(29-7.2)-0.8=29-(7.2+0.8)=29-8=21$